Ganciclovir (DHPG)

A to Z Drug Facts

 Action Inhibits cytomegalovirus (CMV) and other virus replication by competitive inhibition of viral DNA polymerases and direct incorporation into viral DNA.

 Indications

IV: Treatment of CMV retinitis in immunocompromised patients, including patients with AIDS; prevention of CMV disease in organ transplant patients at risk for CMV.

Oral: Alternative to the IV formulation for maintenance treatment of CMV retinitis in immunocompromised patients, including patients with AIDS, in whom retinitis is stable following appropriate induction therapy and for whom the risk of more rapid progression is balanced by the benefit associated with avoiding daily IV infusions.

Treatment of other CMV infections (pneumonitis, gastroenteritis, hepatitis) in some immunocompromised patients.

 Contraindications Hypersensitivity to acyclovir.

 Route/Dosage

CMV Retinitis or Prevention in Transplant Recipients:M

ADULTS: IV Induction: 5 mg/kg over 1 hr q 12 hr for 14 to 21 days. Maintenance: 5 mg/kg over 1 hr qd or 6 mg/kg over 1 hr/day 5 days/wk (max 6 mg/kg over 1 hr). PO Following induction treatment, the recommended maintenance dose of oral ganciclovir is 1000 mg 3 times/day with food. Alternatively, the dosing regimen of 500 mg 6 times/day q 3 hr with food, during waking hours, may be used. IV Implant 1 implant for 5 to 8 mo. Implant may be removed and replaced depending upon the progression of retinitis.

Decreased Renal Function:

ADULTS: IV Induction: 2.5 mg/kg q 1 hr (Ccr 50 to 79 mL/min/1.73 m²); 2.5 mg/kg q 24 hr (Ccr 25 to 49 mL/min/1.73 m²); 1.25 mg/kg q 24 hr (Ccr < 25 mL/min/1.73 m²). Maintenance: 50% induction dose. PO 1000 mg tid or 500 mg q 3 h, 6 times/day (creatine clearance 70 mL/min or greater); 1500 mg qd or 500 mg tid (Ccr 50 to 69 mL/min); 1000 mg qd or 500 mg bid (Ccr 25 to 49 mL/min); 500 mg qd (Ccr 10 to 24); 500 mg 3 times/wk, following hemodialysis (< 1 mL/min).

 Interactions

Amphotericin B, cyclosporine, nephrotoxic drugs: May increase serum creatinine.

Cytotoxic drugs: May cause added toxicity.

Imipenem-cilastatin: May cause generalized seizures.

Probenecid: May reduce renal clearance and increase serum levels of ganciclovir.

Zidovudine: Both zidovudine and ganciclovir can cause granulocytopenia; combination therapy at full dose may not be tolerated.

Do not mix with other drugs.

 Lab Test Interferences None well documented.

 Adverse Reactions

CNS: Headache; confusion. DERMATOLOGIC: Rash; phlebitis or pain at injection site. GU: Renal toxicity. HEMATOLOGIC: Granulocytopenia; thrombocytopenia; anemia. HEPATIC: Abnormal LFT results. OTHER: Sepsis; fever.

 Precautions

Pregnancy: Category C. Lactation: Undetermined. Advise against nursing during and for ³ 72 hr after treatment. Children: Safety and efficacy not established. Carcinogenesis: Ganciclovir is potentially carcinogenic. Cytopenia: Use drug with caution in patients with preexisting cytopenias; granulocytopenia is common. Hydration: Accompany administration by adequate hydration because ganciclovir is excreted by the kidneys. Renal impairment: Use drug cautiously and adjust dose. Renal toxicity: Carefully monitor renal function, especially when other nephrotoxic drugs are given. Retinal detachment: Has occurred; relationship to drug undetermined.

 Administration/Storage

IV

• Reconstitute with 10 mL of Sterile Water for Injection (do not use bacteriostatic water or other solutions) and shake well to dissolve drug.
• Prepare infusion solution by mixing with 0.9% Sodium Chloride for Injection, D5W, Ringer’s Injection or Lactated Ringer’s Injection.
• Wear gloves, gown, and mask while preparing solution.
• Use caution during administration to prevent personal exposure.
• Do not infuse at concentrations > 10 mg/mL.
• Use infusion pump to prevent rapid or bolus injection.
• Administer only into veins that permit rapid dilution and distribution.
• Do not administer to patients with absolute neutrophil count of < 500/mm³ or platelet count of < 50,000/mm³.
• Refrigerate infusion solution until use but not for > 24 hr.
• Discard reconstituted drug if vial has particulate matter or is discolored.
• Reconstituted solution in vial is stable at room temperature for 12 hr; do not refrigerate.
• Dispose of unused drug with appropriate precautions for nucleoside analog cytotoxic agents.

 Assessment/Interventions

• Obtain patient history, including drug history and any known allergies. Note history of cytopenia or impaired renal function.
• Obtain neutrophil and platelet counts before starting therapy, q 2 days during twice-daily dosing and weekly thereafter.
• Obtain daily neutrophil counts in patients with history of drug-induced leukopenia or in whom neutrophil counts are < 1000/mm³ at initiation of treatment.
• Obtain serum creatinine or measure Ccr ³ q 2 wk.
• Be especially attentive to renal function of elderly.
• Be alert for evidence of new infection and report to health care provider.

 Patient/Family Education

• Give patient and family members instructions regarding handling of ganciclovir and proper disposal techniques when drug is to be administered at home.
• Inform patient that it is important to drink plenty of fluids.
• Teach patient being treated for CMV retinitis that drug is not cure, but it may help to keep symptoms from getting worse.
• Advise CMV retinitis patients to have regular ophthalmologic examinations ³ q 6 wk during treatment.
• Instruct patients to use barrier form of contraception for ³ 90 days after treatment because ganciclovir is potentially teratogenic.
• Explain to men that drug may cause temporary or permanent male infertility.
• Tell patient to avoid crowds and people with infections.
• Instruct patient to report these symptoms to health care provider: Headache, mental status changes, rash, pain at injection site, fever, nausea, unusual bleeding or bruising, black tarry stools, other physical complaints.

Books@Ovid
Copyright © 2003 Facts and Comparisons
David S. Tatro
A to Z Drug Facts